- Women of childbearing potential with a negative serum pregnancy test at screening who are not breast feeding, do not plan to become pregnant during the study, and agree to use an approved method of birth control during the study. Approved methods of birth control are oral, path, injectable or implantable hormonal contraception, intrauterine device, diaphragm plus spermicide, or female condom plus spermicide. Abstinence, partner's use of condoms, and partner's vasectomy are NOT acceptable methods of contraception.